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10-15-2013, 12:40 PM   #1
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Just got a used Sigma 17-50mm 2.8 EX DC HSM is this a problem?

Just pulled the new (to me) lens out of the box with great excitement only to find that it gets a little "stuck" when zooming in and out at the 28mm mark. Is this normal? I had a cheaper Sigma in the past that did this but I thought the EX line wouldn't have the issue. Should I return the lens and try again new or otherwise?
Thanks!

10-15-2013, 01:42 PM   #2
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Hi,

It is a bit difficult to give an answer, as one has to feel the drag / resistance at 28mm. If it is just a little stiffness, I would not care if the lens is otherwise a very good performer.
It is quite difficult to find a "perfect" lens, a little "issue" is often there.
I would test the lens: How precise does the Phase-AF "hit"? Is it necessary to correct a Front / Backfocus Problem and how much has to be dialed in (+/- 2 or +- 10)?
Is there a centering defect? How much is it visible when looking at a photo - is it immediately visible that a corner of the photo is "mushy", while in the opposite corner everything is sharp?
Or is it just barely visible when pixelpeeping and even then hardly noticeable?

When the lens is top, except the little stiffness at 28mm - I would keep it!
10-15-2013, 02:01 PM - 1 Like   #3
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A lot of lenses move through a transition point where one or more groups change direction when zooming. It is really hard to describe what you should feel. I forget with this lens does the outside length remain unchanged when zooming. If so, watch from observing through the front element whether you can detect a change in direction of internal groups as you zoom, and note where this takes place, of lenses that change length just watch the front element
10-15-2013, 02:04 PM   #4
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Is this an issue you've experienced in any of your other lenses? It kind of drives me crazy. It literally feels like the lens should stop zooming back at 28mm. Then you kind of push past it. If you are zooming slowly it is very distinct. Less so if you are zooming quickly. What I can say is that my Kit DA felt 100% more smooth that this does.

QuoteOriginally posted by Lowell Goudge Quote
A lot of lenses move through a transition point where one or more groups change direction when zooming. It is really hard to describe what you should feel. I forget with this lens does the outside length remain unchanged when zooming. If so, watch from observing through the front element whether you can detect a change in direction of internal groups as you zoom, and note where this takes place, of lenses that change length just watch the front element
Seems as though everything is moving in the same direction when the sticking happens. If I hold the lens upside-down it is less noticeable


Last edited by JeremytheIndian; 10-15-2013 at 02:12 PM.
10-15-2013, 03:06 PM   #5
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My series 1 70-210/3.5 has this, it is a push pull zoom so really noticeable . Also the Pentax FA power zooms (at least the two I own) also exhibit this

I have not tried my more modern sigma and tamron zooms
10-15-2013, 03:08 PM   #6
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QuoteOriginally posted by Lowell Goudge Quote
A lot of lenses move through a transition point where one or more groups change direction when zooming. It is really hard to describe what you should feel. I forget with this lens does the outside length remain unchanged when zooming. If so, watch from observing through the front element whether you can detect a change in direction of internal groups as you zoom, and note where this takes place, of lenses that change length just watch the front element
A good post, which I just liked. I think that this is the cause for the "sticking" at a given focal length.
10-15-2013, 03:29 PM   #7
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So if I replace this otherwise good used lens with a new one I may be disappointed to find that the new one will also stick? I paid about $460 from Adorama so I saved about $100 off new with current promos
10-15-2013, 03:58 PM   #8
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From "Canonrumors forum":

"I find the zoom to be way too stiff on my copy for zooms during video. It's fine for stills. To zoom during video, you will want a sturdy tripod, though I'm not sure even that and a "follow zoom" will counteract the stiffness and yield no shake."

From "Photography-on-the.net":

"I really love this lens for photography but for video not so much. The OS works great but the short focus throw and the stiff as heck zoom ring are a real damper when doing video. Even on a heavy tripod it's impossible to get a smooth zoom. Are the comparable Tamrons and Canon lenses the same way?"

It is probable that you exchange your lens and get another "sticky" one, but this time with a "mushy" corner.
But if you got patience...there are people that return 5 lenses until they are satisfied - that's not for me.

10-15-2013, 05:02 PM   #9
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Well, compared to your kit lens the Sigma is moving really heavy stuff when zooming and that is one of the reasons for the varying stiffness, I can feel it with some of my bigger lenses too. Note that it can get less distinct with age if you're lucky.
10-15-2013, 05:12 PM   #10
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QuoteOriginally posted by VisualDarkness Quote
Well, compared to your kit lens the Sigma is moving really heavy stuff when zooming and that is one of the reasons for the varying stiffness, I can feel it with some of my bigger lenses too. Note that it can get less distinct with age if you're lucky.
I'm sure that my DA^ 50-135 is also moving heavy stuff but it's zoom is buttery smooth. I guess I just feel like a premium lens should have a nice smooth feel to it. I'd even be alright with stiff throughout the zoom range but it's like it is hitting a bump.
10-15-2013, 05:19 PM   #11
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QuoteOriginally posted by JeremytheIndian Quote
I'm sure that my DA^ 50-135 is also moving heavy stuff but it's zoom is buttery smooth. I guess I just feel like a premium lens should have a nice smooth feel to it. I'd even be alright with stiff throughout the zoom range but it's like it is hitting a bump.
It all depends on the design, how the lenses moves and how long the throw is at the place where most lenses turn their movement direction. All lens designs are different.
10-15-2013, 05:23 PM   #12
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Try A New One

How about this: Next time you're near a large camera store, go in and ask to see a new one? Don't even tell them you already have one, just try a sample, on any camera body. If a new one hits the same 'bump', well...there you go!
Just an idea.
Ron
10-15-2013, 05:30 PM   #13
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QuoteOriginally posted by rbefly Quote
How about this: Next time you're near a large camera store, go in and ask to see a new one? Don't even tell them you already have one, just try a sample, on any camera body. If a new one hits the same 'bump', well...there you go!
Just an idea.
Ron
Good idea however, I live in BFE as far as camera stores are concerned. I think i'm gonna try and PM some members who have reviewed the lens on the site.
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